Omega-3 fatty acids shown to prevent diabetes complications

Type 2 diabetes accounts for 90% to 95% of all diabetes cases in the U.S. and is most prevalent in middle-age or older adults, and in people who are overweight. In type 2 diabetes, the pancreas produces insulin, but the cells are unable to make effective use of it; this results in high levels of glucose (blood sugar) circulating in the body.

Weight and diet affect diabetes in ways that are still being studied. Both body fat and fat circulating in the bloodstream appear to hinder the ability of body cells to use insulin. The pancreas compensates by producing additional insulin, but as people put on more and more weight, the pancreas slowly becomes unable to keep up with the added demand. Sometimes, the strain becomes so great that the function of the pancreas deteriorates, and type 2 diabetes results.

In search of therapies to help manage blood glucose levels and prevent complications associated with type 2 diabetes, researchers have investigated the effects of supplemental omega-3 essential fatty acids.

Omega-3 essential fatty acids are found in certain oils and cold-water fish, such as salmon, mackerel, halibut, and herring. These fatty acids, including eicosapentaenoic acid (EPA), alpha-linolenic acid (ALA), and docosahexaenoic acid (DHA), have been linked to an improvement in glucose-insulin metabolism.

Dr. Jing Luo and colleagues conducted a study that examined insulin-stimulated glucose metabolism in adipocytes (fat cells) of insulin-resistant rats.

For six weeks, rats were fed a diet containing 50% sucrose and either 30% dietary fish oil (containing omega-3 essential fatty acids) or 30% vegetable and animal oils, which were used as control oils. A third reference group was fed a standard diet of 62% corn starch and 13% fat.

At the end of the study, Dr. Luo and colleagues stated in the Journal of Nutrition that fish oil effectively lowered insulin, glucose, cholesterol, and blood lipid levels in insulin-resistant rats. In fact, investigators concluded that "...six weeks of consuming 30% dietary fish oil had beneficial effects on insulin and lipid concentrations and on insulin action at the adipocyte level."

While further studies need to be conducted on omega-3 essential fatty acids, this study demonstrates the beneficial effects of fish oil in relation to insulin resistance and type 2 diabetes.

SOURCE: J Nutr 1996;126(8);1951-58.

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